Despite their name, Crabeaters eats mainly krill; crabs form only a small portion of the seals' diet. Crabeaters live at the edge of pack ice and are normally solitary animals. However during the breeding season, they will form small family groups consisting of the mother, father and a pup.
The Crabeater seal accounts for over half of the world's seal population. Estimates place the Crabeater's population in excess of 30 million. Its population explosion is possibly due to the decline of whales, the Crabeater's chief competition for krill.
The Crabeater's main predator is the killer whale (or orca). Occasionally whales will bump an ice floe which has seals on it in order to knock seal into the water. Leopard Seals also prey on the Crabeater, although typically only on the young.